//@json
function main(tbl){
	tbl.put("table","sys_user")
	let sys_user = dao.fetch(tbl.table,Cnd.where("username","=",tbl.username))
	if(!isEmpty(sys_user)){
		return {code:-1,msg:"用户名已存在"}
	}
	try {
		$mager(tbl)
		return {code:0}
	} catch (e) {
		return {code:404}
	}
}